About those potholes

Posted
Friday, March 16, 2018 1:26 pm

Q. Is there a way to prevent potholes? My driveway is made of the same thing as the street, but has few cracks or sunken spots. My street, by comparison, is terrible. They fill the holes every year, and every year the holes come back. In 20 years, I haven’t seen my street repaved, like the others in my neighborhood. I complain but nothing gets done. What can be done to permanently fix the street? I know that highways don’t have as many problems, so there must be a way to avoid all the holes, car accidents and repairs. What is it?

A. It doesn’t take a roads scholar to answer this question, but it does take well-spent money, good design, management and timing to get the job to last. Whether it’s an airport runway, highway, parking lot or driveway, the design of roadways is based on the use.

The first major roadway projects were built for heavy wear and tear, and the expense was justified because the roads were part of a major military expenditure to move vast amounts of heavy military equipment, like tanks, transports and Jeeps over land quickly and efficiently through the National Highway Act. Once in a while you’ll find a pocked stretch of highway, but for the most part, the amount of potholed highway, compared with local streets, is minimal, so it is possible to have better roads.

Like any good construction job, if you want it to last, you have to use better, stronger, correctly installed materials. That seems easier said than done. It comes at a higher price, although part of the problem is management and cooperative communications. For example, when a brand new paved road is cut up for water, sewer or power lines that could have been scheduled before paving, it creates uneven pavement, and what are referred to as “cold joints.” These joints, as with any material, allow water to seep in and the joined materials to “let go,” separate from each other and open up the area where potholes begin.

A road flexes up and down like a trampoline when a large vehicle, loaded with tons of material, glides across. Temperature extremes are especially hard on roads. Think of a road as a thin ribbon compared with the miles of earth beneath it. The earth, every inch of land, has water running beneath it. The moisture in the earth below any built structure, especially flimsy roadways, freezes and expands, as does the moisture seeping in between the roadway’s materials. Freezing causes water to expand, which in turn causes extreme pressure, pushing against the roadway materials, breaking them apart. There are formulations of specially adhered materials that create air spaces to allow the base below the paving to drain and keep water from lingering and expanding. Combined with a routine of preventive surface sealers, fixing road sections, not just spots, like highways are done, would cost more but save more in the long run.